Production of zinc sulfate.



' No Drawing. l

STA- s PRODUCTION OF ZINC SULFATE.

- tion of the same.

This invention relates to a process for producing zinc sulfate or other zinc compounds from zinc ores.

The object of the invention is to convert zinc blende into zinc sulfate without the use of sulfuric acid, and to effect this conversion With a high percentage yield.

Hitherto, I believe, it has not been possible to convert more than to of the zinc in the ,zinc blends into, zinc sulfate by smelting. Y

I To accomplish the desired end I treat the zinc blende as follows.:-With the zinc blende I mixa suitable quantity'of zinc oxid,

or some substance-such as calamin or zinc carbonate containing sufficient zinc and oxygen. The zinc blend'e used should contain substantially enough sulfur in the form of other sulfids to form zinc'sulfate by a reac- 'tion' between the blende and the oxid or calamin. Should the ore' not contain enough sulfur as just stated, free sulfur may also be mixed with the 'blende to supply this dc ficiency. In zinc blende containing also considerable percentages of sulfid of iron or other non-zincic sulfids, sufficient sulfur is obtained from the sulfids to combine with the zinc oxid, carbonate or calamin and oxygen to form zinc sulfate. The proportion; of zinc oxid, carbonate or calamin -'to the blende must therefore be regulated. accord ing to the percentage of sulfur in the blende.

For example, with 100 lbs. of impure zine blende containing 50 to of Z1110 sulfid and 20 to 30% of sulfid of iron, may be mixed 15 to 25-lbs. of zinc oxid orja'quantity of calamin or carbonate containing. at least as much of zinc as the oxid. The 7% to 11 lbs. of sulfur contained in the sulfid of iron will furnish sulfur tocombine With -the oxid of zinc to form zinc sulfate. Such a mixture of zinc blende and zinc oxid is then roasted. in a furnace of any suitable description which is not hermetically sealed but into which the air can enter without producing strong currents of air through the furnace, This mixture is roasted in Specificationiof Letters Patent.

Patented June 15, 1915.

. Application filed April 2, 1915. Serial No. 13,818. Y

such a furnace at about 400 to 500 C, and W1th the result that substantially the following reaction occurs:

As this reaction indicates, the sulfid-of iron or other non-zincic sulfide are converted into OXldS, furnishing some sulfur to com:

bine with zinc oxid to form zinc sulfate.

Oxygen, moreover, is brought into thereaction, being furnished by the air which has I access to the furnace, so that thetotah 10' uantity of zinc, (both as sulfid andas oxid) 1n the mixture is converted into zinc sulfate; It-may bethat zinc oxid acts as a carrier of the oxygen to the sulfid, for I find that it is possible to thus convert zinc blende into zinc sulfate at the comparatively low temperature stated.

It is known that zinc sulfid and zinc oxid form a compound ZnSZnO at low temtially allof the zinc, oxid a ndlsulfidhave' been converted into zinc sulfate' The re-' sulting mixture of zinclsulfa'te and other substances, such as oXids,-;'-is' agitated in ,Water preferably in hot waterto'leich out the zinc sulfate, andthe resulting aqueous solution is decanted-,and may then, be further treated to remove impurities if necessary'or thought desirable.

The zinc oxid usedmay beprepared in any suitable way; "For. instancefI first oxidize the zinc blende, (which m be either comparatively pure zinc sulfidver may be contaminated with larger or vsmalleramounts of other sulfids or-otherimpurities) in a'.

roasting furnace at about 800430 900 (3., and until the zinc sulfid has been substantially'all converted into zinc oxid. V

If instead of using zinc oxid, obtained by v the preliminary roasting abovedescribed, I

mix calamin or "zinc carbonate with a suitable amount of fresh zinc blende as above described, the carbonate is decomposed into carbon dioxidfand 'zinc oxid; and the latter furnishes the zinc oxid required for the above reaction and effects aboverdescribed. 1

- Thenovel process herein describedhas general application in the production of zinc sulfate, but is particularly suitable in the production of pure stable zinc sulfate used to react with barium sulfid in the production of inalterable White lithopone.

I claim as my invention 1. The method of producing. zinc sulfate,

to 400 to500 C. in an oxidizing atmosphere.

4. The method of producing zinc sulfate, which consists in mixing a blende comprising zinc sulfid and sulfid of iron with calm min or zinc carbonate, and heating to400 to 500 C. in air free from strong currents.

5. The method of producing zinc sulfate, which consists in heating a mixture of zinc sulfid, sulfid of iron and zinc oxic' in an oxidizing atn'iosphere at a temperature below low red heat.

0. The method of producing zinc sulfate, which consists in heating a mixture of zinc sulfid and sulfur in anotherforin with zinc oxid in an oxidizing atmosphere at a ternperature below red heat.

RAMONBONASTRE LLOPART. 

